1. Field
Embodiments of the subject matter described herein relate generally to aircraft structures. More particularly, embodiments of the subject matter relate to a compliant crown panel for an aircraft.
2. Background
The forward pressure bulkhead in an aircraft is located at the nose of the fuselage, and it serves as a barrier for the pressurized interior cabin environment. The front side of the forward pressure bulkhead is typically surrounded by the radome or “nose cone” of the aircraft, which houses an antenna and/or other equipment for the aircraft. The inside of the radome is not pressurized, i.e., it is exposed to ambient air conditions. The radome is typically formed from a lightweight and electromagnetic transparent material such as fiberglass. Consequently, the forward pressure bulkhead is designed to provide additional protection against foreign objects, such as birds, which may strike the nose of the aircraft.
Conventional forward pressure bulkheads are designed to rigidly withstand impacts by providing a “brick wall” protection mode. In other words, conventional forward pressure bulkheads are engineered to resist bird penetration with very low structural deflection. In this regard, such forward pressure bulkheads utilize rigid reinforcement beams, ribs, or other components that support the main bulkhead panel. Therefore, such forward pressure bulkheads are typically fabricated from many separate components that are welded, riveted, or otherwise connected together to form the desired structure. The resulting structure can include a large parts count, which increases the cost of the forward pressure bulkhead. In addition, the resulting structure is, by design, structurally inefficient.
The crown panel of an aircraft is the area beginning above the cockpit windows and typically extending aft to a structural frame member of the aircraft. Like the forward pressure bulkhead, this area is prone to bird strike and in-flight hail due to its exposed location near the front of the fuselage. In this area there is a steep angle of incidence relative to the direction of flight (typically about 25 to 30 degrees). Conventional crown panels utilize substantial structure and frame elements designed to resist deflection and penetration by foreign objects. Consequently, prior art crown panel assemblies utilize heavy reinforcement beams, ribs, or other components that support the exposed crown panel skin. Moreover, such prior art crown panel assemblies may require a large parts count, which increases the material and manufacturing cost of the crown panel.